Magnetic means for stirring mercury in an ignitron



Feb. 6, 1940. J, SLEElAN ET AL 2,189,619

MAGNETIC MEANS FOR STIRRING MERCURY IN AN IGNITRON Filed July 9, 1938ATTORNEY APatented Fvebl, 1940 andere PATENT orrica 'MAGNETIC MEANS FOR'STIRRING l MERCURY IN AN IGNI'IRON l yJoseph slepian, Pittsburgh, andwilliam E. Pakala, Forest Hills, Pa., assignors to Westinghouse-Electric & Manufacturing v Company,

East Pittsburgh, Pa., vania` 4a corporation ofPennsyl- Application July9, 1938, vSerial No. 218,354

' 7 Claims.

Our invention relates to a vapor electric device and more particularly'to means-for stirring the liquid cathode generally used insuch devices.

In the voperation of vapor. electric discharge 1 5 devices of the typeutilizing a liquid pool cathode,

such as a mercury pool, aconsiderable amount of heaty is set free at thecathode spot terminal of 'the electric arc. Due to the lowcoeflcient ofthermal conductivity rof mercury, this heat cannot escape readily by vconduction through the mercury lto the cooling surfaces and as a resultthe surface of the mercury attains a high tem-v for stirringl themercury cathode vigorously and'v directing it in paths alongy coolingsurfaces. Briefly, we submerge magnetic devices in the mercury in such aposition that'm'agnetic elds are set up which react with thefelectriccurrents i in the mercury thus producing motion of the mercury. Moreparticularly, we submerge permanentimagnets, preferably of the horseshoetype, in thev mercury, thus creating a numberk of "strong magneticfields therein. Moreover, we lrnayrnount guide of some non-conductingmaterial, such as a quartz block, in the mercury just below the tip ofAthe make-alive electrode in case suchvr an electrode is used todirectthe owof` current which is being conducted by the mercury. Whenthe current which is flowing into theI mercury crosses the 'magneticfields, a sidewise force is imparted to the: mercury according to wellknown principles of electromag- .netism and a number of` whirls areestablished.

By positioning a cooling coil in the mercury In actual.

tions in the temperature gradient along various points of the mercurysurface. Y yv Another object of our invention'is'to provide 'means formore effectively cooling .the mercury cathode of a vapor dischargedevice. j

Othervobjects and advantages of our invention will be apparent from thefollowing detailed description taken in conjunction with theaccompanying drawing, inwhich:

Figure 1 vis a sectional elevation of a vapor electric discharge deviceemploying magnets forstirring the mercury cathode showing a v'ieW takenalong the lines I-I of Fig. 2,and'

Fig. 2 is a sectional view of the mercury cathode illustrating thelocation of the magnets "and cooling coils andthe paths assumed by `themercury when a reaction of the magnetic elduponthe current in' themercury takes place. j

Referring more particularly'to l, 'illustrate a vapor electric converter3 comprising an evacuated vcontainer 5, an anode l' and i a cathode. 9commonly comprising mercury vin the lower portion of the container 5.submerged withinrthe cathode 9 are a plurality of permat nent magnets ll preferably ofthe horseshoe type 'for setting up a number of magneticfields therein. The magnets H may be either of the permanent type or ofthe temporary type, such as electromagnets. It is to be understood,however, that while we have shown a specific type of magnet Il, we donot wish to limit ourselves thereby to any one" design or class ofmagnets vI l. Preferably, the magnets AIl are insulated from the mercurycathode 9 by completelycovering them With some insulating coating y(notshown) such as a vitreous enamel and supporting them by supporting legsI2 secured `to thebase of the I3 or groove inthe yoke lportionml ,toaffordja passageway vfor the flow of mercury, aswe shall hereafterdescribe mo're.fully.y In mounting 'the 'magnets Il in place, we prefer.to arrange the magnets l l so as to have unlike poleslofadjacentmagnetic iield.`

In contact with the mercury i slightly projecting below its surface, wehave container 5. Each ofthe magnets `Il has a notchy magnets lltogether,` thereby being,able` to.`,as-. certain the-,direction of thelinesof force of `the Y.

ycathode 9 and K provided a make-alive electrode l'l composed of v In acentral portion of the mercury cathode 9 and located below themake-alive electrode I1, we have provided a suitable guide 2l made ofsome non-conducting material such as a quartz block to direct the now ofcurrent conducted by the mercury towards the magnetic fields surroundingthe horseshoe magnets ll. The guide 2i may be supported by providing vaplurality of supporting legs 22 fastened to the container 5. It is to beunderstood, however, that the tip of make-alive electrode il need .notbein contact with the guiding element 2| as suchen arrangement serves nouseful purpose.

Referring to Fig. 2, we have provided a'cooling coil 23 which may bemounted radially, spirally or otherwise in the mercury cathode'l.Iii-order' to obtain a more rapid heat transfer from the hottest pointin the mercury cathode 9 to the cooling coil 23, we prefer touseza;coilf23 formed of material having a high coe'lcient of heatconductivity such as copper, the exterior surface -of which vmaybecoated `with a suitable nonamalgamable materal'such as -anickel plating.Preferably, we `wishlto locate various portions of thecooling-coil :23.in suchspositions that the mercury, Whenstirred, -will.be incloseproximity to .thecoil 23. The coolingmedium used may be -freshwater and:is admitted into the coil -23 -through .an inlet valve -25 Whichrnay-beused to regulate the flow of water.

.-Inthe'operaticn-.oi' our device 3, a suitable current :is permitted tolow. through they make-alive electrode t1 ywhereupon a-cathode spot isproduced at the junction of themalre-alive electrode YIl .and thecathode material .9 andunder proper conditions .of-potential, thecathode spot` expands into-an arc, Yufnichimmediately transfers to the.anode 'l and the;rectifying process has begun. In accordancewiththeacceptedconvention of cur- ,rent flow, `the rectified -currentisconsidered as .owingfrom `theanode 'u'.to the.cathode il and:thence-,through the cathode lead v.21. However, the-guiding element 2 lwhichis centrally mounted :in Ithe mercury `cathode ,S directs `thecurrent being conductedbythe .mercury into the magneticiields set up Aby.the magnets Il. In order to.determine the .direction of motion of themercury, 4the .application ofthe familiar left-hand .rule formotorswhich states that whena conductor.carrying-alcurrent, which in ourcase is mercury,.is.plaeed.in a magnetic eld,.a ,sidewise thrust isimparted. As a .result Aof `such motor action of the .eld upon thecurrent inthe mercury, ,a .pluralityof whirls 2.8 .are ,established in,the mercury cathode.andaccordingtc observa- ,.tions in the laboratoryWherefouitmagnets i l are used, eight such .whirls29 were created.

:Although wehaveshown and ,described a cerltain .specic `embodiment -ofour invention, `it is .apparent vthat ,changesiand modifications maybefmade ltherein .without departing vfrom jthe spirit `andnscope ofourinvention. We desiratherefore, `that only .such..limitations shall beimposed as arelembodied 1in 'theaccompanying claims or as 'maybenecessitated'by the prior art.

vWe claim as curinvention:

l. In'an electrical discharge device comprising a plurality oi principalelectrodes at least one of which is a liquid metallic cathode, meansdisposed in said cathode for setting up a magnetic eld, means forestablishing a current in said cathode and means centrally disposed insaid cathode for directing ,the current in said cathode into saidmagnetic eld.

2. In an electrical discharge device comprising ,a liquid metalliccathode, means submerged in said `cathode vfor establishing magneticelds, guiding means directing the current in said cathode so as to besubjected to the influence of said magnetic fields.

3. An electric discharge device comprising a liquid metallic cathode, aplurality o1 permanent magnets vsubmerged in said cathode, an insulatingcovering cn each of said magnets, a guide of nonconductingmaterial fordirecting the current into magnetic fields set up by said magnetswhereby a plurality of whirls are set up in said cathode.

Ji. In -an electric discharge device comprising .ev'acuatedcontainen aliquid metal cathode in saidcontainer, an auxiliary electrode in fcontact with said-cathode in a central portion therecf `orinitiatingvalc-athode spot, a plurality of :.permanentfmagnets `submerged. in saidcathode,

magnets having their pole pieces in -the -neighoorhoodci said cathodespot, the magnetic elds set up'byfsaid magnets moving portions'of said`liquid cathode ,adjacent said cathode spot s towardslthe .walls ofsaid'container when said cathode is carrying current.

5 An electric discharge device comprising a plurality .of principalelectrodes at least one 'of .which is.liquid,an auxiliary electrode incontact f with and centrallydisposed in said liquid, -a plurality-ofpermanentmagnets submerged in said liquid electrode, means forestablishinga current insaidliquid, a non-conducting-guiding elementYicrdirecting thecurrent in said liquid electrode intomagnetic ields setup by said magnets,fsaid rguiding elementcentrally disposed in saidliquid .-electrodebut spaced from said auxiliary electrode.

.6. ,In an ,electricdischarge device comprisinga liquid metalliccathode, an auxiliary electrode .havinga tip portion in contact with andcentrally .disposed in said cathode, a block of nonconductingmaterialbeneath said .tip portion of said .auxiliary electrode but spacedtherefrom,

magnetic means forsetting up a plurality ofmagnetic .eldsin `saidcathode, said magnetic elds subjectingsaid liquid cathode into apluralityof whirlingmovements when said liquid cathodeis carryingcurrent and cooling means arranged within said cathode as to besubstantially .in parallel with said whirling cathode.

Y?.y Apparatus for stirring mercury in a vapor electric convertercomprising in combination .a

plurality .ofpermanent magnets uniformly disposed in said mercury andaguiding element `of A, non-conducting material for influencing thcpathof said mercury when `conducting a currentinto -electrie 'fields set upby said magnets whereby said mercury is subjected to whirling movements.

JOSEPH SLEPIAN. WILLIAM E. PAKALA.

